PCI: Enable ARI if dev and upstream bridge support it; disable otherwise (b0cc6020) · Commits · 戴 / test

Currently, we enable ARI in a device's upstream bridge if the bridge and the device support it. But we never disable ARI, even if the device is removed and replaced with a device that doesn't support ARI. This means that if we hot-remove an ARI device and replace it with a non-ARI multi-function device, we find only function 0 of the new device because the upstream bridge still has ARI enabled, and next_ari_fn() only returns function 0 for the new non-ARI device. This patch disables ARI in the upstream bridge if the device doesn't support ARI. See the PCIe spec, r3.0, sec 6.13. [bhelgaas: changelog, function comment] Signed-off-by:

Yijing Wang <wangyijing@huawei.com> Signed-off-by:

Jiang Liu <jiang.liu@huawei.com> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

+12 −5

Original line number	Diff line number	Diff line
		@@ -2069,6 +2069,9 @@ void pci_free_cap_save_buffers(struct pci_dev *dev)
		/**
		* pci_enable_ari - enable ARI forwarding if hardware support it
		* @dev: the PCI device
		*
		* If @dev and its upstream bridge both support ARI, enable ARI in the
		* bridge. Otherwise, disable ARI in the bridge.
		*/
		void pci_enable_ari(struct pci_dev *dev)
		{
		@@ -2078,9 +2081,6 @@ void pci_enable_ari(struct pci_dev *dev)
		if (pcie_ari_disabled \|\| !pci_is_pcie(dev) \|\| dev->devfn)
		return;

		if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI))
		return;

		bridge = dev->bus->self;
		if (!bridge)
		return;
		@@ -2089,8 +2089,15 @@ void pci_enable_ari(struct pci_dev *dev)
		if (!(cap & PCI_EXP_DEVCAP2_ARI))
		return;

		pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2, PCI_EXP_DEVCTL2_ARI);
		if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI)) {
		pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
		PCI_EXP_DEVCTL2_ARI);
		bridge->ari_enabled = 1;
		} else {
		pcie_capability_clear_word(bridge, PCI_EXP_DEVCTL2,
		PCI_EXP_DEVCTL2_ARI);
		bridge->ari_enabled = 0;
		}
		}

		/**

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